The present invention relates to an apparatus for detecting faults to which may occur or initially exist in a running electric rotary machine to thereby determine if the machine is operating in a normal state mechanically as well as electrically.
Detector apparatus utilizing a vibration measuring instrument or a thermometer has hitherto been used for the detection of the eccentric revolution or vibration of the rotor shaft and wear of bearings. A detector comprising an annular electrode disposed adjacent to the rotating shaft is also known from Japanese Utility Model Application Publication No. 19,281/67. Another known type of detector is composed of a proximity switch provided near the rotating shaft of the electric rotary machine as taught in Japanese Utility Model Application Publication No. 15,880/68. Furthermore, Japanese Utility Model Application Publication No. 1,864/69 discloses a detector apparatus comprising a ring disposed in the vicinity of the rotating shaft of the rotary machine, whereby the degree or amount of the abrasion of the bearings is determined on the basic of the rotational movement of said ring.
The difficulties or disadvantages common to all the hitherto known detector apparatus of the above mentioned types reside in the fact that the accuracy of detection is directly influenced by inevitable tolerance or error in machining as well as the mounting position of the detecting member to be installed since these detector components consist of mechanical elements. Another drawback is that a spatial restriction is imposed because extra space is required for the installation of the detector elements.
An object of the present invention is to provide an improved apparatus for detecting the wear or abrasion of the bearing or bearings in an electric rotary machine, in which the disadvantages of the prior detectors are at least substantially eliminated.
Another object of the present invention is to provide an improved detector for sensing an eccentric revolutional operating state of an electric rotary machine.
Still another object of the present invention is to provide a detector for detecting unbalanced current in the main windings of an electric rotary machine.